[pve-devel] implementation of a dhcp service in proxmox ?

[Alexandre DERUMIER]

>>Why does a dhcp server needs an IP (dhcp is layer 2)? 

That's what I thinked too, but from wikipedia:

http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol

1) client : DHCPDISCOVER : UDP Src=0.0.0.0 sPort=68 Dest=255.255.255.255 dPort=67
2) server : DHCPOFFER : UDP Src=192.168.1.1 sPort=67 Dest=255.255.255.255 dPort=68
3) client: DHCPREQUEST: DHCPREQUEST UDP Src=0.0.0.0 sPort=68 Dest=192.168.1.1 dPort=67
4) server : DHCPACK : UDP Src=192.168.1.1 sPort=67 Dest=255.255.255.255 dPort=68

Seem that the problem if DHCPREQUEST, which send packet to a specific dhcpserver ip


I have tried with dnsmasq,listening to bridge,

without ip:
dnsmasq-dhcp[179128]: DHCP packet received on vmbr1v95 which has no address

with an ip on bridge, but on different network range:

dnsmasq-dhcp[577367]: no address range available for DHCP request via vmbr1v95



----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com>, pve-devel at pve.proxmox.com 
Envoyé: Mardi 21 Mai 2013 09:54:12 
Objet: RE: [pve-devel] implementation of a dhcp service in proxmox ? 

> I think we need 1 ip for the dhcp server, for each range. (1 range by bridge-vlan 
> ?). 
> 
> So do we need to assign 1 ip to each bridge ? (including vmbrXvX) 
> 
> I would like to have 1 dhcp server by proxmox host to manage dhcp for local vm 
> only, so do I need 1 ip for dhcp server by bridge by host ?. 
> 
> I don't known if we can use a "internal" ip by bridge and reuse it on each host ? 

Why dos a dhcp server needs an IP (dhcp is layer 2)? 

> openstack seem to create a new tap with an ip for the dhcp server plugged to 
> bridge. 
> (http://techbackground.blogspot.fr/2013/05/debugging-quantum-dhcp-and- 
> open-vswitch.html) 
> 
> 
> NAT network 
> ----------- 
> For Nat, I think we only need static ip configuration for each vm nic. 
> 
> 
> Seem that currently proxmox use netdev, so userland. 
> qemu documentation seem to say that performance are lower than tap. (lot of 
> overhead) http://wiki.qemu.org/Documentation/Networking. 
> 
> Advantage of netdev is that we can use an dhcp server embbeded in qemu ex : - 
> netdev user,id=mynet0,net=192.168.76.0/24,dhcpstart=192.168.76.9 
> 
> If we use tap, can the dhcp listen directly to the tap interface ? What is the dhcp 
> server ip in this case ? 

The plan is to replace that using a tap device (as described in http://tjworld.net/wiki/Linux/KvmQemuEasyRoutedNetwork) 

> 
> 
> Routed network 
> -------------- 
> Don't have played with routed network yet, but interesting article here: 
> http://tjworld.net/wiki/Linux/KvmQemuEasyRoutedNetwork